/*
 * Copyright 2006 IBM Corporation.
 *
 */
package javax.portlet;

/**
 * The <CODE>MimeResponse</CODE> defines the base interface to assist a
 * portlet in returning MIME content. 
 *
 * @since 2.0
 */
public interface MimeResponse extends PortletResponse {

    /**
     * Property to set the expiration time in seconds for this response using
     * the <code>setProperty</code> method intended to be used in 
     * forwarded or included servlets/JSPs.
     * <P>
     * If the expiration value is set to <code>0</code>, caching is disabled for this
     * portlet; if the value is set to <code>-1</code>, the cache does not expire.
     * <p>
     * A default can be defined in the portlet deployment descriptor
     * with the <code>expiration-cache<code> tag, otherwise it is <code>0</code>.
     * <p>
     * Non-integer values are treated as <code>0</code>.
     * <p>
     * The value is <code>"portlet.expiration-cache"</code>.
     * 
     * @see CacheControl
     */
    public static final String EXPIRATION_CACHE = "portlet.expiration-cache";

    /**
     * Property to set the cache scope for this response using the
     * <code>setProperty</code> method intended to be used in 
     * forwarded or included servlets/JSPs.
     * <P>
     * Predefined cache scopes are: <code>PUBLIC_SCOPE</code> and <code>PRIVATE_SCOPE</code>.
     * <p>
     * A default can be defined in the portlet deployment descriptor
     * with the <code>cache-scope<code> tag, otherwise it is <code>PRIVATE_SCOPE</code>.
     * <p>
     * Values that are not either <code>PUBLIC_SCOPE</code> or <code>PRIVATE_SCOPE</code>
     * are treated as <code>PRIVATE_SCOPE</code>.
     * <p>
     * The value is <code>"portlet.cache-scope"</code>.
     * 
     * @see CacheControl
     * @since 2.0
     */
    public static final String CACHE_SCOPE = "portlet.cache-scope";

    /**
     * Public cache scope, indicating that the cache entry can be shared across
     * users. The value is <code>"portlet.public-scope"</code>.
     * 
     * @since 2.0
     */
    public static final String PUBLIC_SCOPE = "portlet.public-scope";

    /**
     * Private cache scope, indicating that the cache entry must not be shared
     * across users. The value is <code>"portlet.private-scope"</code>.
     * 
     * @since 2.0
     */
    public static final String PRIVATE_SCOPE = "portlet.private-scope";
    
    /**
     * Property to tell the portlet container the new ETag for this response
     * intended to be used in forwarded or included servlets/JSPs.
     * <p>
     * This property needs to be set using the <code>setProperty</code> method. 
     * <P>
     * The value is <code>"portlet.ETag "</code>.
     * 
     * @see CacheControl
     * @since 2.0
     */
    public static final String ETAG = "portlet.ETag";

    /**
     * Property to tell the portlet container to use the cached markup
     * for the validation token provided in the request. This property 
     * needs to be set using the <code>setProperty</code> method with a non-null
     * value and is intended to be used in forwarded or included servlets/JSPs.
     * The value itself is not evaluated. 
     * <P>
     * The value is <code>"portlet.use-cached-content "</code>.
     * 
     * @see CacheControl
     * @since 2.0
     */
    public static final String USE_CACHED_CONTENT = "portlet.use-cached-content";

    
    /**
     * Property intended to be a hint to the portal application that the returned 
     * content is completely namespaced. 
     * This includes all markup id elements, form fields, etc.
     * One example where this is might be used is for portal applications that
     * are form-based and thus need to re-write any forms included in the portlet
     * markup. 
     * <p>
     * This property  needs to be set using the <code>setProperty</code> method with a non-null
     * value. The value itself is not evaluated. 
     * <p>
     * The value is <code>"X-JAVAX-PORTLET-NAMESPACED-RESPONSE"</code>.
     * 
     * @since 2.0
     */
    public static final String NAMESPACED_RESPONSE = "X-JAVAX-PORTLET-NAMESPACED-RESPONSE";
    
    /**
     * Property intended to be a hint to the portal application that the provided
     * DOM element should be added to the markup head section of the response to the
     * client.
     * <p>
     * Support for this property is optional and the portlet can verify if the
     * calling portal supports this property via the <code>MARKUP_HEAD_ELEMENT_SUPPORT</code>
     * property on the <code>PortalContext</code>.
     * <p>
     * Even if the calling portal support this property delivery of the DOM
     * element to the client cannot be guaranteed, e.g. due to possible security
     * rules of the portal application or elements that conflict with the
     * response of other portlets.
     * <p>
     * This property  needs to be set using the 
     * <code>setProperty(String key,org.w3c.dom.Element element)</code>
     * method.
     * <p>
     * The value is <code>"javax.portlet.markup.head.element"</code>.
     *
     * @since 2.0
     */
    public static final String MARKUP_HEAD_ELEMENT = "javax.portlet.markup.head.element";
    
    
    /**
     * Returns the MIME type that can be used to contribute markup to the render
     * response.
     * <p>
     * If no content type was set previously using the {@link #setContentType}
     * method this method returns <code>null</code>.
     * 
     * @see #setContentType
     * 
     * @return the MIME type of the response, or <code>null</code> if no
     *         content type is set
     */
    public String getContentType();

    /**
     * Sets the MIME type for the response. The portlet should set the
     * content type before calling {@link #getWriter} or
     * {@link #getPortletOutputStream}. If the content type is not 
     * the {@link PortletRequest#getResponseContentType} value is
     * set as response content type by the portlet container.
     * <p>
     * Calling <code>setContentType</code> after <code>getWriter</code> or
     * <code>getOutputStream</code> does not change the content type.
     * <p>
     * 
     * @param type
     *            the content MIME type
     * 
     * @see PortletRequest#getResponseContentTypes
     * @see #getContentType
     */
    public void setContentType(String type);

    /**
     * Returns the name of the charset used for the MIME body sent in this
     * response.
     * 
     * <p>
     * See <a href="http://ds.internic.net/rfc/rfc2045.txt">RFC 2047</a> for
     * more information about character encoding and MIME.
     * 
     * @return a <code>String</code> specifying the name of the charset, for
     *         example, <code>ISO-8859-1</code>
     * 
     */
    public String getCharacterEncoding();

    /**
     * Returns a PrintWriter object that can send character text to the portal.
     * <p>
     * Before calling this method the content type of the render response should
     * be set using the {@link #setContentType} method.
     * <p>
     * Either this method or {@link #getPortletOutputStream} may be called to
     * write the body, not both.
     * 
     * @return a <code>PrintWriter</code> object that can return character
     *         data to the portal
     * 
     * @exception java.io.IOException
     *                if an input or output exception occurred
     * @exception java.lang.IllegalStateException
     *                if the <code>getPortletOutputStream</code> method has
     *                been called on this response.
     * 
     * @see #setContentType
     * @see #getPortletOutputStream
     */
    public java.io.PrintWriter getWriter() throws java.io.IOException;

    /**
     * Returns the locale assigned to the response.
     * 
     * @return Locale of this response
     */
    public java.util.Locale getLocale();

    /**
     * Sets the preferred buffer size for the body of the response. The portlet
     * container will use a buffer at least as large as the size requested.
     * <p>
     * This method must be called before any response body content is written;
     * if content has been written, or the portlet container does not support
     * buffering, this method may throw an <code>IllegalStateException</code>.
     * 
     * @param size
     *            the preferred buffer size
     * 
     * @exception java.lang.IllegalStateException
     *                if this method is called after content has been written,
     *                or the portlet container does not support buffering
     * 
     * @see #getBufferSize
     * @see #flushBuffer
     * @see #isCommitted
     * @see #reset
     */
    public void setBufferSize(int size);

    /**
     * Returns the actual buffer size used for the response. If no buffering is
     * used, this method returns 0.
     * 
     * @return the actual buffer size used
     * 
     * @see #setBufferSize
     * @see #flushBuffer
     * @see #isCommitted
     * @see #reset
     */
    public int getBufferSize();

    /**
     * Forces any content in the buffer to be written to the underlying output stream. A call to
     * this method automatically commits the response.
     * 
     * @exception java.io.IOException
     *                if an error occurred when writing the output
     * 
     * @see #setBufferSize
     * @see #getBufferSize
     * @see #isCommitted
     * @see #reset
     */
    public void flushBuffer() throws java.io.IOException;

    /**
     * Clears the content of the underlying buffer in the response without
     * clearing properties set. If the response has been committed, this method
     * throws an <code>IllegalStateException</code>.
     * 
     * @exception IllegalStateException
     *                if this method is called after response is committed
     * 
     * @see #setBufferSize
     * @see #getBufferSize
     * @see #isCommitted
     * @see #reset
     */
    public void resetBuffer();

    /**
     * Returns a boolean indicating if the response has been committed.
     * 
     * @return a boolean indicating if the response has been committed
     * 
     * @see #setBufferSize
     * @see #getBufferSize
     * @see #flushBuffer
     * @see #reset
     */
    public boolean isCommitted();

    /**
     * Clears any data that exists in the buffer as well as the properties set.
     * If the response has been committed, this method throws an
     * <code>IllegalStateException</code>.
     * 
     * @exception java.lang.IllegalStateException
     *                if the response has already been committed
     * 
     * @see #setBufferSize
     * @see #getBufferSize
     * @see #flushBuffer
     * @see #isCommitted
     */
    public void reset();

    /**
     * Returns a <code>OutputStream</code> suitable for writing binary data in
     * the response. The portlet container does not encode the binary data.
     * <p>
     * Before calling this method the content type of the render response must
     * be set using the {@link #setContentType} method.
     * <p>
     * Calling <code>flush()</code> on the OutputStream commits the response.
     * <p>
     * Either this method or {@link #getWriter} may be called to write the body,
     * not both.
     * 
     * @return a <code>OutputStream</code> for writing binary data
     * 
     * @exception java.lang.IllegalStateException
     *                if the <code>getWriter</code> method has been called on
     *                this response.
     * 
     * @exception java.io.IOException
     *                if an input or output exception occurred
     * 
     * @see #setContentType
     * @see #getWriter
     */
    public java.io.OutputStream getPortletOutputStream()
            throws java.io.IOException;

	/**
     * Creates a portlet URL targeting the portlet. If no portlet mode, window
     * state or security modifier is set in the PortletURL the current values
     * are preserved. If a request is triggered by the PortletURL, it results in
     * a render request.
     * <p>
     * The returned URL can be further extended by adding portlet-specific
     * parameters and portlet modes and window states.
     * <p>
     * The created URL will per default not contain any parameters of the
     * current render request.
     * 
     * @return a portlet render URL
     */
	public PortletURL createRenderURL();

	/**
     * Creates a portlet URL targeting the portlet. If no portlet mode, window
     * state or security modifier is set in the PortletURL the current values
     * are preserved. If a request is triggered by the PortletURL, it results in
     * an action request.
     * <p>
     * The returned URL can be further extended by adding portlet-specific
     * parameters and portlet modes and window states.
     * <p>
     * The created URL will per default not contain any parameters of the
     * current render request.
     * 
     * @return a portlet action URL
     */
	public PortletURL createActionURL();

	/**
     * Creates a portlet URL targeting the portlet. If no security modifier is
     * set in the PortletURL the current values are preserved. The current
     * render parameters, portlet mode and window state are preserved.
     * <p>
     * If a request is triggered by the PortletURL, it results in a serve
     * resource request of the <code>ResourceServingPortlet</code> interface.
     * <p>
     * The returned URL can be further extended by adding portlet-specific
     * parameters .
     * <p>
     * The created URL will per default contain the current 
     * cacheability setting of the parent resource. 
     * If no parent resource is available, <code>PAGE</code> is the default.
     * 
     * @since 2.0
     * @return a portlet resource URL
     */
	public ResourceURL createResourceURL();


    
    /**
     * Returns the cache control object allowing to set
     * specific cache settings valid for the markup
     * returned in this response.
     * 
     * @return  Cache control for the current response.
     * 
     * @since 2.0
     */
    public CacheControl getCacheControl();

    


}
